text: If a graph of the mass or mole yield of fission products against the atomic number of the fragments is drawn then it has two peaks, one in the area zirconium through to palladium and one at xenon through to neodymium. This is because the fission event causes the nucleus to split in an asymmetric manner, as nuclei closer to magic numbers are more stable.
  Yield vs. Z - This is a typical distribution for the fission of uranium. Note that in the calculations used to make this graph the activation of fission products was ignored and the fission was assumed to occur in a single moment rather than a length of time. In this bar chart results are shown for different cooling times (time after fission).
  Because of the stability of nuclei with even numbers of protons and/or neutrons the curve of yield against element is not a smooth curve. It tends to alternate.
  In general, the higher the energy of the state that undergoes nuclear fission, the more likely a symmetric fission is, hence as the neutron energy increases and/or the energy of the fissile atom increases, the valley between the two peaks becomes more shallow; for instance, the curve of yield against mass for Pu-239 has a more shallow valley than that observed for U-235, when the neutrons are thermal neutrons. The curves for the fission of the later actinides tend to make even more shallow valleys. In extreme cases such as Fm, only one peak is seen.
  Yield is usually expressed relative to number of fissioning nuclei, not the number of fission product nuclei, that is, yields should sum to 200%.
  The table in the next section ("Ordered by yield") gives yields for notable radioactive (with half-lives greater than one year, plus iodine-131) fission products, and (the few most absorptive) neutron poison fission products, from thermal neutron fission of U-235 (typical of nuclear power reactors), computed from [http://books.elsevier.com/companions/075067136X/pdfs/Yield.bas?mscssid=HAX80JCKT7RB8LS6F675GU2LM83N1CL6].
  The yields in the table sum to only 45.5522%, including 34.8401% which have half-lives greater than one year:
  The remainder and the unlisted 54.4478% decay with half-lives less than one year into nonradioactive nuclei.
  This is before accounting for the effects of any subsequent neutron capture; e.g.:
  * Xe capturing a neutron and becoming nearly stable Xe, rather than decaying to Cs which is radioactive with a half-life of 2.3 million years
  * Nonradioactive Cs capturing a neutron and becoming Cs, which is radioactive with a half-life of 2 years
  * Many of the fission products with mass 147 or greater such as Pm, Sm, Sm, and Eu have significant cross sections for neutron capture, so that one heavy fission product atom can undergo multiple successive neutron captures.
  Besides fission products, the other types of radioactive products are
  * plutonium containing Pu, Pu, Pu, Pu, and Pu,
  * minor actinides including Np, Am, Am, curium isotopes, and perhaps californium
  * reprocessed uranium containing U and other isotopes
  * tritium
  * activation products of neutron capture by the reactor or bomb structure or the environment